Cellulose ester



me e

@me @am ester'if mlxt re of e after its sbabuza'ti' aida" more 'or' eitn acid depends upon the kind and the vo1ume of the Sve hydrOlY-Zation., ,if necessary, with addition reaction mixture. With increasing volume the 0f a Suitable dlllenb. fOr l'lStaIlCeaCetC aCd,0I percentage of the promoter generally decreases. the primary solution is subjected G0 a hydIOlySS 55- The favorable effect of sulfates used besides a. With Water, fOr inSGaIlCe, until Solubility in 913e- 1116Kk iirst added-l6.4 grams of sodium acetategdis- 35. l 'i cooled state are :then added during a quarter of lduced yfrom which no pressed. 9 grams of pyridine and 18 grams of cent.

tinued at about 20-30 C. until a homogeneousY fiber pulp is produced in which the celluloseis esteried as far as the monoacetate.v Then are solved in 50 grams of glacial acetic acid and after Well mixing there are further added'. 25.6 grams Vof sulfuric acid, likewise diluted Witl1'50 grams of glacial acetic acid.

When the acetylation is fcomplete, the ester is*` rendered soluble in acetone by adding Water to the acetylation mixture. The cellulose butyrate acetate thus obtained yields a film which is appreciably less sensitive to Water than is the pure .cellulose acetate lrn. k

Example .3j-The operations are those f de-. scribed in lExample 1, but in the second stage there areadded instead of 16.4 grams of sodium acetate 17 grams of sodium nitrate and. after y 1A; of an hour' 25.6 grams of sulfuric. acid. A nitrateacetate of a small content of nitrogen goodv is obtained. It ryields a lm Whichhas a strengthand is very stable to water.

Example 4.-400 grams of nitrated cotton containing 2 per cent of nitrogen, 1200 grams of glacial acetic acid, and '4 grams of. sulfuric acid.v

6 hours at '20-25. C.,

are stirred or shaken for 8 00 grams of acetic anhydrideV in a strongly an hour. The .temperature rises to about 30-40D C. VThe mass `is then'cooled and kept at 20C. until va uniform fibrous magma 'has been promoreV liquid can be exsulfuric` acid dissolved in 90 grams `Tof glacial acetic 'acid are now added within 10 minutes.

The temperature is maintainedat 20?-30? C.Y andY afterl about 11/2 hours the. mass is smooth and free from bers. Dilutevaqueousfsulfuric acid is added and hydrolysis isy effected until the mass The nitrate acetate.y ob-` is soluble in acetone..

tained has a nitrogen content of about 1,3, per

' In theffollovving claims the term` cellulosic compound?? is .intended to include as Well-genua-l ine cellulose as Apretreated cellulosecontaining however, still unsubstituted hydroxyl groups.r

What I yclaim f 1. A process for esterifying a'cellulose comfpound containing l esterifiabl .hydroxyl Vgroups Which comprises the presence of a diluent tvith an` amount of sul` furic acid comprising less than 2 per centfof free sulfuric acid' calculatedon the weight of the at least one compound of the group,

neutral and acid salts, and neutral and'.l acid esters of VVsulfuricgacid, .said compounds being cellulose compound, adding-a fatty acid anhydride,` esterifying the`r cellulose compound partially, and treatingithe-reaction product thus obtained with a mixture of free sulfurie'acid and soluble in the .reaction mixture.`

treating' the starting material in consisting of Y K smooth and free from bers. Y 2. A ,process for vesterifying a cellulose com@ Y pound containing -esteriable hydroxyl Igroups.

which comprises treating the starting material in the presence of a :fatty acid with an amount of sulfuric acid comprising less than 2 Aper cent.. of free sulfuric acid calculated on thekweight of the. cellulose compound, adding a fatty acid anhydride, esterifying v the cellulose vcompound partially and treating theireaction product thus obtained Witha mixture of vfree'sulfuric acid and at least' one compound of vthe' group consisting of acid salts and acid' esters of sulfuric acid, said compounds being soluble inthe reaction mixture.

J3. Aprocess for esterifying a cellulose rcompound containing 'esteriable hydroxyl groups which `comprises treating 400 parts by weight of short-Viibered, bleached linters with 1200 parts by Weight of acetic acid and 4 parts by weight of sule furic acid ofA 95 per cent strength, adding 1200 parts by weight of acetic anhydride and stirring the mixture at about 20 to 30 C. until a uniform, smeary ber pulp is produced from which no more liquid can be expressed, and treating the reaction product thus obtained Witha mixture of 16.4 parts by Weight of anhydrousy sodium acetate and `25.6 parts by Weight ofsulfuric acid of 95 per cent strength, corresponding to 24 partsv by weight of sodium bsulfate and 6 parts by Weightof rfree sulfuric acid, the yreagents being preferably dissolved in 5,0 to 100 parts by Weight of acetic acid, during which second stage the temperature of the reaction mixture may rise to about 35 C., until lthe mass. Ais smooth Yand freeV from' fibers. l .f

4. A process for esterifyingv a cellulose com#v pound containing esteriable hydroxyl groups'y which comprises treating 400 parts by Weight of comminuted bleached linters With 800 parts by Weight of glacial acetic acid, 400'parts by Weight of Ubutyric, anhydride .and 4 parts by Weight of sulfuric acid'of 9519er cent strength,'adding 1200 parts `by Weight of acetic anhydride and 'stirring the mixture at about 20 to 30C. until a homogeneous b'er pulp isproducedin Whichthe celluloseis esteried as far as the monoacetate, and treating the reaction product thus obtained With 1;'7 parts by Weight of'sodium nitrate diluted in 50 `parts by'weightof acetic glacial acid and 25.6 parts by Weight ofV sulfuric acid dilutedv in 50 parts' by Weight 'Of acetic acid `until acetylation isfcomplete.

5. A processfor, esterifying' a cellulose compound .containing esterilable hydroxyl vgroups which comprises in Ya rst stagejtreating` A400 parts by Weight of nitrated cottoncontaining 2 per cent of nitrogen With 1200 parts by Weight, of glacial acetic acid and 4 parts by weight ofl sulfuric acid of 95 per cent strength at'about 20 to 25C., adding 800 parts. by weightof acetic anhydride in a stronglycooled state While alloW-.

ing thetemperature'of the mass to rise to about Bil-40, C., cooling hereafter the mass to a temperature of 20. C. and keeping it atthis tern-v perature until'a uniform brous magmaha's been produced fromywhichno morerliquid can be expressed, andy treating .the reaction product thusk obtained with 9 partsby Weight of pyridinel and 18 parts by Weight ofsulfuric acid dissolvedin 90 parts -hy Weight of glacial acetic acid ata temperature of Aaboutx20 to 30 C., until the mass is FRANZBECKER. i

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